1992～ 1996年 82只流道冲蚀刺穿的 8 H5 17钻头的统计数据表明 ,冲蚀失效钻头的年投诉率达 5 0 %左右。针对该型钻头流道的结构缺陷 ,提出了改进措施 :(1)改进钻头流道形状 ,增加分流结构 ,使流道截面积变化平缓 ;(2 )适当调整水孔入口段的直径 ,使其与喷嘴入口的台肩从升坎变为降坎 ;(3)修改喷嘴的装配尺寸及其公差 ,减小喷嘴的轴向间隙和径向间隙 ,并适当增大喷嘴密封圈的最小压缩量 ;(4)用螺纹环取代卡簧锁紧喷嘴 ,以消除喷嘴的轴向间隙 ;(5 )增大水孔入口处圆弧的曲率半径 ,尽可能减小凸台 ,使流线更趋平缓。改进后的钻头纯钻时 70h以上未出现流道冲蚀失效现象 ,耐冲蚀寿命比改进前提高近 1倍 Statistics from 82 H5 17 drills stabbed by 82 runners from 1992 to 1996 show that the annual complaint rate of erosion-failure drills is about 50%. Aiming at the structural defects of this type of drill bit, some improvement measures are put forward: (1) to improve the shape of the bit flow passage and increase the shunt structure so as to make the cross section of the flow path change gently; (2) to adjust the diameter of the water inlet section (3) Modify the nozzle assembly dimensions and tolerances to reduce the nozzle axial clearance and radial clearance, and the appropriate increase in the nozzle seal minimum compression; (4) Replace the circlip locking nozzle with a threaded ring to eliminate the axial clearance of the nozzle; (5) Increase the radius of curvature of the circular arc at the inlet of the water hole, and reduce the projection as much as possible to make the flowline more gentle. The improved drill bit pure drill 70h when there is no flow erosion erosion phenomenon, erosion-resistant life expectancy improved nearly 1 times